---Hello, this is Mike. Is Dr. Li in?---Sorry, he_________ to the west of Africa to help the patients there.A.has been B. is going C. has gone
--They are making too much here. I can’t do anything. --I will tell them to keep quiet .
--Why don’t you read this book? --It’s not necessary to read this book .There isn’tuseful in it .
--I don’t think teenagers should be allowed to smoke. --.
You should really _______ smoking. It’s a terrible habit.
Sixteen-year-olds shouldn’t ______ to go to an Internet bar.